A tie-bolt is used in a gas turbine engine to secure some of the components mounted around a shaft. The tie-bolt is coaxially mounted at the end of the shaft.
The tie-bolts are initially pre-stretched when mounted in a gas turbine engine. The pre-stretching ensures a very strong hold of the component or components to be retained and is required to compensate for the thermal expansion of the tie-bolt due to the surrounding heated environment.
Traditionally, the pre-stretching requires that a nut be positioned by hand along the tie-shaft while the tie-bolt is pulled using an hydraulic actuator. The nut is rotated until it abuts the component to be held. The problem is that the final position of the nut will not necessarily be exactly the same from one engine to other due to various factors. As a result, the pre-stretching force varies within a given range from one engine to another. This generally requires that the pre-stretching be higher than required so as to ensure a minimal pre-stretching level at all times.
Accordingly, there is a need to provide an improved tie-bolt and an improved method that allow the pre-stretching to be more precise than with conventional arrangements.